1. Field of the Invention
The invention relates generally to an electrically operated control device and, more specifically, to a compact control device for reversible equipment and the like.
2. Discussion of Related Art
An apparatus or electronic switches, which control electrical equipment that is powered by batteries and which connect electric motors to sources supplying them with current, are known in different embodiments. In particular, such an apparatus or electronic switches are used with manually operated electrical equipment such as drills, cordless screwdrivers, etc. In effecting such control, the current, which is supplied by a source to the driving motor of the manually operated electrical equipment, flows through a power semiconductor. The conductivity of the power semiconductor is controlled by the position of a trigger handle in such a manner that it is possible to control the power to the electric motor.
Appropriate switches, such as those manufactured and sold, for example, by the CAPAX Company, etc., are usually constructed so that at least the power transistor must be mounted as an individual module together with a necessary heat sink. The module is mounted externally to the electronic switch housing and at a place within the equipment whose motor is to be controlled or regulated. In this manner, it is possible to cool the power semiconductor adequately, for example, by attaching it to the housing wall, etc., so that damage during operation is largely eliminated.
The known construction of, for example, the CAPAX electronic switch is such that an actually closed housing is not provided. In addition to the power transistor component, the housing is constructed by fitting together three distinctly different housing components. For example, mounted on the known housing there is a separate right/left switch, which itself is connected to the housing with two connectors along the outside of the housing and additionally with three further connecting leads, which must be routed from the housing to the individual module of the power transistor.
All electrical connections are direct whether internal or also leading to the outside, that is, to the source to the motor connections. This makes it necessary to introduce tinned wire ends into the housing through openings, in which the tinned wire ends are locked by latching tonques.
This is costly and not necessarily reliable, because such plug-in connections may become loose are cumbersome, and are not dust-proof so that dirt may enter the interior of the housing through the wire openings. Moreover, the housing is not designed to be particularly dust-proof.
The installation of such battery control switches on an electronic device is also complicated, expensive and, if for no other reason than because of the external, electrical connecting lines, not always sufficiently foolproof. Mistakes can occur if the personnel is not trained adequately. Furthermore, within the equipment supplied with such an electronic switch, there are a plurality of electrical connecting lines which run outside of the approximately box-shaped housing of the electronic switch, and can therefore also be subjected to interference or caused to malfunction.
The invention generally is directed to such an electronic switch for controlling motors of, for example, manually operated electrical equipment, the current for which is supplied by an appropriate source or batteries. However, it is self-evident that this is merely a preferred embodiment of the invention and that the use of such a switch with other battery-operated equipment and systems is also possible.
It would be desirable to provide a supply circuit powered by batteries, particularly for motor driving mechanisms, that accommodates within a closed, tightly limited switch housing a power semiconductor, which controls the load such as the motor, and which nevertheless ensures an adequate dissipation of heat.